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Bluetail
Thursday 11th December 2003, 10:56
Unless I'm much mistaken, we had a pretty exceptional autumn for Yellow-broweds in the UK. Has anyone seen any estimates of how many we had? Was it a record?

Jason

Jane Turner
Thursday 11th December 2003, 15:29
I had 3 to 5 in one day on the West Coast. That was cetrainly a record! There was an estimate ion BB I think... just no idea where I filed the copy :(

Michael Frankis
Thursday 11th December 2003, 15:38
Not far off 300 according to the December BB, from mid Sept to mid Oct. Not a patch on 1985 when the total (Rare bird in Britain and Ireland) was around 600.

Michael

Bluetail
Thursday 11th December 2003, 21:17
Thanks, Michael. I had a feeling that might be the case.

Jason

StevieEvans
Thursday 11th December 2003, 21:21
Hi
Any thoughts on where all these lost little birds go ?
S

Michael Frankis
Thursday 11th December 2003, 21:34
Hi Stevie,

The latest suggestion is thet they're not lost at all, that they are deliberately coming here to winter, with every intention of returning to Siberia to breed next spring. Some are getting found in winter now, but there's such a huge area of under-watched conifer plantations for them to hide away through the winter that the vast majority will never get found (like Goldcrests etc, they are a conifer forest species for preference).

So if anyone fancies searching the spruce plantations of southwest Ireland or south Wales, for example . . .

And if anyone's wondering what they'll eat - count the number of Green Spruce Aphids on even a small Sitka Spruce twig in winter. No shortage at all.

Michael

Stephen Dunstan
Thursday 11th December 2003, 21:51
I'm not surprised it isn't a record year, with precisely one in Lancashire. We had as many Dusky's!

Stephen Dunstan
Thursday 11th December 2003, 21:54
Michael,

I should have read your stuff properly. If the suggestion you mention was the case wouldn't a decent proportion be adults? This isn't to say that displaced first years couldn't find enough food here and return in the spring.

Stephen.

StevieEvans
Thursday 11th December 2003, 21:57
Thats good!
To me it takes the shine off seeing an unusual species - if i imagine its 'never getting home'
I noticed there had been some inland records this year.

I have systematically searched through various belts & bigger blocks of conifers (when weather was too bad for normal birding) while locating Leowls, i would say that at best i could only ident about 2 out of 10 'Goldcrests' by sight.
What else is in there is anyones guess....

What about birds returning in spring? Any on East coast then?

Stevie

Bluetail
Thursday 11th December 2003, 22:13
What about birds returning in spring? Any on East coast then?
Excellent point. I don't recall there being many, if any, records - but then, I haven't been looking out for them.

Jason

Edward woodwood
Thursday 11th December 2003, 22:39
There is a very good article by James Gilroy and Alex Lees on vagrancy and 'pseudo vagrancy' in a BB 9:427-438

Bluetail
Thursday 11th December 2003, 22:53
Have you got the reference right there, Tim? Sounds very old....?

Jason

Edward woodwood
Thursday 11th December 2003, 22:57
oops, well spotted Jason
they would have been very prescient indeed
Vol 96

I'm blaming the wine!

Michael Frankis
Thursday 11th December 2003, 23:10
Spring birds, and autumn adults, are stronger and more experienced than fresh juveniles - so they're much less likely to get caught up in bad weather and dumped unceremoniously in difficult spots like offshore and have to struggle to land. The healthy adults will be flyover jobs, as they're fit enough not to need to crash out on the first coastal bush.

Michael

Jane Turner
Thursday 11th December 2003, 23:14
I was seawatching once and was astonished to see a summ plum GND fly stright over my head and inland.

Bluetail
Thursday 11th December 2003, 23:20
But if it's UK-wintering birds migrating "home", then surely getting dumped by bad weather doesn't enter into it. Isn't it more similar to autumn migration on the south coast, where birds pile up while waiting for a weather window? However, spring migration is more urgent than in autumn so the picture may be different. What happens on, say, the French or Danish coasts in spring? Do our summer visitors congregate there is there no visible migration? If the former, you'd expect something similar as the UK Yellow-broweds return east.

Jason

Michael Frankis
Thursday 11th December 2003, 23:39
Hi Jason,

Think of Redwings in spring - they just gradually melt away and disappear, you don't see many of them on coastal migration points in spring, either (despite that there's a million or so leaving the British Isles every spring). The typical successful adult Yellow-browed probably feeds up in some big plantation dozens of miles inland, perhaps Kielder Forest, and set off well-prepared on a single flight to a plantation in the middle of Denmark, feed up there 3 or 4 days, next stop the pine forests of Estonia.

A week or ten days (two or three flights + feeding stopovers) later he's singing on territory in a spruce forest in the Urals, having arrived a week or two before his competitors coming twice the distance from Thailand. A very neat little set-up, in fact!

Not actually very different to the east European Blackcaps that winter here - the only real difference is that those like bird tables, so they tend to get found in winter.

Michael

Bluetail
Thursday 11th December 2003, 23:50
Thanks, Michael. Nice little winter project for when we want something different, then!

Jason

Michael Frankis
Thursday 11th December 2003, 23:56
Hi Jason,

One more thought that came to me just after posting - I wonder if there is a relationship between the increase in Y-brow numbers observed, and improved winter survival because of the massive expansion in Sitka Spruce plantations in the post-war period: these would be getting to an attractive tree size in the late 70s and 80s.

Traditionally, the increase has been put down to the increase in the number of birders looking, but it could well be a real increase.

Makes one wonder, if there's a couple of thousand Yellow-broweds wintering in Britain & Ireland every year. Just remember there's also over a million hectares of plantations for them to hide in!

Michael

StevieEvans
Friday 12th December 2003, 00:06
Nice theory MF!

I agree, just 'cos something hasn't been seen doesn't mean it isn't there!

S

Stephen Dunstan
Friday 12th December 2003, 06:14
Jane,

You are in the wrong thread. I welcome your support in the GND thread!

Call me strange but I will give searching large conifer plantations for wintering Yellow-broweds a miss!

Stephen.

Jane Turner
Friday 12th December 2003, 07:03
I get confused so easily.......

Bluetail
Friday 12th December 2003, 11:40
I appreciate it was only a gentle musing, Michael, but I find it a bit hard to believe there are anything like a couple of thousand undiscovered Yellow-broweds wintering in the UK. Don't see why there shouldn't be a few, though.

Jason

HH75
Friday 12th December 2003, 15:44
Hi all,
While I believe that the likes of Yellow-browed Warbler move through NW Europe in a purposeful manner rather than as chance vagrants,I also think that very few of these spend the winter this far north(with the proviso that most of these would occur in underwatched areas/habitat types).Most probably continue south to S.France/Spain(a similar situation applies to Richard's Pipit,which is sometimes seen in winter in Britain and Ireland but occurs in decent numbers in S.Europe)?
Harry H

Jane Turner
Friday 12th December 2003, 18:32
How common are they at Gibraltar?

Michael Frankis
Friday 12th December 2003, 19:51
Hi Jason,

Think of it this way - 2,000 Y-brows in a million hectares of plantations is one per five square kilometers. Of a habitat that most birders never bother to look in, and where it is very difficult to see a bird because of the very dense canopy. Bit of a needle in a haystack job!

But yes, some (particularly the Y-brows seen in southern England) may well be heading on to France or Spain as well as Ireland.

Michael

StevieEvans
Friday 12th December 2003, 23:04
Hi Jason,

Think of it this way - 2,000 Y-brows in a million hectares of plantations is one per five square kilometers. Of a habitat that most birders never bother to look in, and where it is very difficult to see a bird because of the very dense canopy. Bit of a needle in a haystack job!

But yes, some (particularly the Y-brows seen in southern England) may well be heading on to France or Spain as well as Ireland.

Michael

MF et al.
Birdguides report of a bird at Upton Warren, Worcs, today.

S

sparrowbirder
Wednesday 17th December 2003, 17:13
Michael, yellow broweds do seem to turn up at some strange places when they are found in winter, often inland sites etc,doesnt seem to be any pattern to them,so your theory sounds spot on, will this mean as the "migration" gene is passed on more and more be wintering thiis way, remember one at Inskip lancs in the early 80s,it was unusual then,its getting commoner all the time, I believe there are a few around in the country at the moment!!

Michael Frankis
Wednesday 17th December 2003, 18:00
Remember . . . . you read it here first!! o:D :D

sparrowbirder
Thursday 18th December 2003, 07:57
Does this theory only apply to palearctic migrants!! or do nearctic migrants "mean" to come here too!!

Michael Frankis
Thursday 18th December 2003, 10:38
Hi Andy,

As Greenland Wheatears also breed in NE Canada, one could call them nearctic migrants that mean to come here - but otherwise, no, at least as far as passerines are concerned. Too much of a struggle for them to cross the Atlantic back again in the spring, against the prevailing winds: the survival rate would be far too low to make it a successful strategy.

Non-passerines, yes; all the (Red) Knot that winter in Britain breed in Greenland and/or Canada, as do quite a lot of Turnstone and some Great Northern Divers, Ringed Plovers, Sanderling and pale-bellied Brant Geese.

Michael

sparrowbirder
Thursday 18th December 2003, 10:56
are we only talking about yellow broweds here!! been the odd winter record of dusky warbler, pallass etc are these doing the same thing,also rare thrushes etc,, also have they always done this,or is it a recent trend,if so why!! could all the recent records just be the result of more observers on the ground! fascinating subject this I think we have only touched the surface on migration and its vagaries

Michael Frankis
Thursday 18th December 2003, 11:14
Hi Andy,

It has probably always happened to a small extent, but has also probably increased recently for various reasons - (1) global warming has made winters more survivable, (2) the Forestry Commission, as mentioned above (when the FC started in the 1920s, Britain only had about 3% woodland left, and that was mostly deciduous, not much good for wintering warblers), and (3) bird tables (for those occasional Black-throated Thrushes).

Yes, I'd guess the Pallas's and Dusky Warblers are doing the same; as they are coming from further than Yellow-broweds, the selective advantage of heading this way is reduced - instead of half the distance to Thailand for a Urals-raised Yellow-browed, it may be 3/4 for them, and so maybe not enough of an advantage to outweigh the possibly higher winter mortality here compared to Thailand.

I must admit, I am surprised we don't get more Asian thrushes wintering here, as they'd be able to cope with out winters easily. If the ratio of Yellow-broweds & Pallas's to Chiffchaffs was repeated in the ratio of Black-throated & Eyebrowed to Redwings . . . well, it obviously isn't! (and I can't think why!)

Michael

sparrowbirder
Thursday 18th December 2003, 13:29
Maybe they are,but because there are less of them they maybe arent being found as readily,who goes birding on a sheep farm in the middle of wales! How many winter thrush flocks arent accessible to most birders!!Those that do turn up tend to do so around major population centers (stating the obvious I know) dont know what the ratio is between warblers/thrushes on the breeding grounds seem to remember this was covered in a previous thread anyway!

guffers
Thursday 18th December 2003, 16:04
Michael, you say that deciduous trees are not much good for wintering warblers so how come there are good numbers of Goldcrests in deciduous woodland and scrub habitats throughout a British winter ? So if there are plenty of wintering Goldcrests in deciduous woodland in Britain then why should there be a lack of YBW's ? Or do you put this down to natural competition between species ?

david kelly
Thursday 18th December 2003, 16:23
I think that the distribution of eastern thrush records in Britain is related to the number of observers. For instance there are only two records of Black-throated Thrush from mainland Scotland, the remaining fifteen? or so are mostly from Shetland, with a few from Orkney. Even those two records were a hundred years apart. There are huge flocks of Fieldfares and Redwings in the Scottish countryside but where are all their eastern cogeners.

By comparison there are a reasonable number of Black-throated Thrush records from the more urbanised areas of England where there are a lot more birders per square kilometre than there are in any part of Scotland, other than the northern islands in peak passage periods.

David

Michael Frankis
Thursday 18th December 2003, 16:35
Hi Guffers,

Deciduous woods are very much second-rate habitats for Goldcrests - you see them, simply because they are so much more visible with no leaves to conceal them. But with no leaves, there's also much less food. A spruce or pine wood in the UK climate has nearly as much insect food available in winter as there is in summer, unlike deciduous trees, where there's a big peak in summer, and very little in winter.

Interesting fact: the Green Spruce Aphid Elatobium abietinum feeds and breeds actively at temperatures down to -7C (they have anti-freeze in their blood) and are only killed if it goes below -8. Most of lowland Britain rarely gets that cold, so there's usually high populations of this aphid in Sitka Spruce plantations. Most aphids on deciduous trees are killed as soon as it drops below 0C, with only the tiny eggs lasting through the winter - not much food there.

Michael